James Naismith invented the sport of basketball in 1891 as well as writing the rule book. He is also often credited with introducing the first football helmet.

James A. Naismith, Bachelor of Arts, Master of Arts (postgraduate), Doctor of Medicine, and Doctor of Divinity, was the inventor of the sport of basketball. The majority of his 13 Rules of Basketball are in effect in the National Basketball Association (NBA) to this day. Naismith was himself an outstanding athlete. He was elected a member of numerous Hall of Fames.

13 Rules of Basketball (as written by James Naismith)

1. The ball may be thrown in any direction with one or both hands.
2. The ball may be batted in any direction with one or both hands, but never with the fist.
3. A player cannot run with the ball. The player must throw it from the spot on which he catches it, allowance to be made for a man running at good speed.
4. The ball must be held by the hands. The arms or body must not be used for holding it.
5. No shouldering, holding, pushing, striking or tripping in any way of an opponent. The first infringement of this rule by any person shall count as a foul; the second shall disqualify him until the next goal is made or, if there was evident intent to injure the person, for the whole of the game. No substitution shall be allowed.
6. A foul is striking at the ball with the fist, violations of Rules three and four and such as described in Rule five.
7. If either side makes three consecutive fouls it shall count as a goal for the opponent.
8. A goal shall be made when the ball is thrown or batted from the grounds into the basket and stays there, providing those defending the goal do not touch or disturb the goal. If the ball rests on the edges, and the opponent moves the basket, it shall count as a goal.
9. When the ball goes out of bounds, it shall be thrown into the field and played by the first person touching it. In case of dispute the umpire shall throw it straight into the field. The thrower-in is allowed five seconds. If he holds it longer, it shall go to the opponent. If any side persists in delaying the game, the umpire shall call a foul on them.
10. The umpire shall be the judge of the men and shall note the fouls and notify the referee when three consecutive fouls have been made. He shall have power to disqualify men according to Rule five.
11. The referee shall be judge of the ball and shall decide when the ball is in play, in bounds, to which side it belongs, and shall keep the time. He shall decide when a goal has been made and keep account of the goals, with any other duties that are usually performed by a referee.
12. The time shall be two fifteen-minute halves, with five minutes rest between.
13. The side making the most goals in that time is declared the winner.